US President Donald Trump approved steep tariffs on solar panel imports in January to protect US producers, triggering an outcry from China, South Korea and even protests from the US solar industry.

China has filed a complaint at the World Trade Organisation (WTO) against the US' 30% safeguard tariffs on solar imports as well as its renewable energy subsidies, claiming that they distort the global PV market - a move which comes as part of wider trade battle between the two global powers.

In response, South Korea, one of USA major sources of washing machine imports, said it will "actively respond to US trade protectionism".

On April 2, China hit back by adopting tariff hikes on 128 US items, including pork, sparkling wine, nuts, and fresh and dried fruit products.

WTO complaints begin with negotiations between parties to the dispute. The widely criticized move escalated tensions between the USA and longstanding trade allies, including Canada, Mexico and European Union nations.

He told the Journal the 25 percent tariffs on steel will rescue an industry important to US national security. The president has also said the tariffs have been created to promote better trade deals.

China lodged its challenge at the WTO on Tuesday, the statement said.

The United States has accused China of using subsidies and bulk manufacturing capacity to drive down prices and put USA competitors out of business in a range of sectors.

The United States and China have slapped tit-for-tat tariffs on tens of billions of dollars worth of goods from each country, with another round of levies scheduled to being next week.